ME CAR DOESNT GO...

My car, a 1987 Delta 88, at 220,000 miles, is not going when I put the pedal down, it goes but its not accelerating. We think it might be the transmission, would you have any other idea what it might be? But if you think it is, could you maybe give me an estimate at how much it would cost to have a transmission put in, and how long it usually takes to do so?